Every utility tariff assigns accounts to rate schedules based on eligibility rules: maximum demand, service voltage, annual usage, metering type or business activity. Those rules are written into the tariff, and many of them require the utility to reassign an account once its load crosses a threshold for a set number of months. In practice, accounts stay on whatever schedule they were set up under. A store that was remodeled with LED lighting and new refrigeration may fall below the demand floor of a large general service schedule, yet keep paying its higher customer and facilities charges for years. A warehouse that added a primary-voltage transformer may still be billed at secondary-voltage rates. The error repeats on every bill until someone compares the account's actual billing determinants against the eligibility language of each schedule it could be served under. Refunds depend on whether the schedule was mandatory or optional: misapplied mandatory assignments are usually refundable for the back-billing period, while optional schedule choices are often corrected going forward only.
How it happens
- The account was set up under a schedule that fit its load years ago, and the utility never ran its periodic eligibility review.
- Load dropped after an efficiency retrofit or a change in operations, putting the account below the schedule's demand floor.
- Service voltage changed (customer-owned transformer, primary service) but the account still carries secondary-voltage pricing.
- A rate case closed or replaced a schedule and the account was mapped to the wrong successor schedule.
- A new tenant or owner opened service and the utility copied the previous occupant's rate code.
How to detect it
- Pull 12 to 24 months of maximum demand, kWh and service voltage for the account and test each against the eligibility clause of every schedule in the tariff.
- Check the schedule code printed on the bill against the code the tariff requires for that demand band, and note any mandatory transfer language.
- Compare peer sites with similar load: if one is on a different schedule, find out why.
- Rebill the last 12 months under each eligible schedule to size the difference before filing.
Evidence the utility will accept
- Twelve or more consecutive bills showing the schedule code and monthly billing determinants
- The tariff sheets in effect for the period, including the eligibility and transfer provisions
- Interval or register demand history from the utility or Green Button data
- Service voltage documentation, such as the service agreement or a transformer ownership record
Recovering the overcharge
We file a written billing dispute with the utility citing the eligibility and transfer language, attach the rebill, and request a corrected rate assignment plus a refund for the full back-billing period the tariff or state rule allows, which is commonly 2 to 3 years. If the schedule was an optional choice rather than a mandatory assignment, many utilities correct it going forward only, and we document the prospective savings instead.